Tool-grinding mechanism



R. L. CARTER TOOL GRINDING MECHANISM Feb. 7, 1928.

Filed Nov. 26. 1926 5 Sheets-Sheet 1 Feb. 7, 1928.

CARTER TOOL GRINDING MECHANI SM Filed Nov. 26. 1926 3 Sheets-Sheet 3 Patented Feb. 7, 1928.

UNETE STATES BAY L. CARTER, OF PHOENIX, NEW YORK.

[FOUL-GRINDING MECHANISM.

Application filed November 28, 1926. Serial No. 150,821.

This invention relates to portable power planes, and the like, and has particular reference to the utilization of the power medium and certain portions of the said devices for sharpening and truing the bits or cutting tools, by which planin routing, or other work is performed.

The object of the invention is to provide a novel and simple jig or holder for supporting the bit while an abrading or sharpening element grinds or dresses the cutting blades of the tool, the said holder being detachably mounted upon the body of the lane, and being provided with novel manually controlled means forrotating and moving the tool axially relatively to the abrading element during the grinding of the several blades. A further objectis to provide an auxiliary shaft for supporting the abrading element, the said shaft being interchangeable with and adapted to be substituted for the normal tool-supporting shaft during the sharpening operations; the auxiliary shaft being attached directly to the armature shaft of the motor that supplies the power for the planing or routing tool, thereby enabling the user of'the plane to readily, quickly and accurately grind the tool, wherever electricity may be available without loss of time, and without requiring an elaborate and expensive grinding mechanism, or the hiring of the grindingwork by skilled tool dressers. A further objectis to provide means for finely and accurately adjusting the said holder for effecting the sharpening and truing-up of the cutting edges of the tool, and for varying the extent of the grinding of the said edges. A further object is to provide a novel gage for guiding the tool during each grinding stroke and for regulating the pitch or bevel of the blades of the tool for effecting suit-able clearance for the said blades. And a further object is to provide a novel bracket for rigidly mounting the body of the plane upon a bench or like support during the grinding operations.

I attain these objects by the means set forth in the detailed description which follows, and as illustrated by the accompanying drawings, in which" Figure 1 is a top plan View of my power plane, in which parts arebroken away for showin the location of the spiral cutting tool. Fig. 2 is a front side elevation of the same. Fig. 3 is a view of the shaft, which supports the cutting tool. Fig. i is an inverted top plan view of the plane showing he holder, which supports the tool in the grinding position; also showing an abrading disc mounted on an auxiliary shaft, which has been substituted for the tool shaft; also showing the bracket by which the motor and plane are clamped to a bench. Fig. 5 is a front side elevation of the same. Fig. 6 is a front end elevation taken in the direction of the arrows in Figs. t and 5. Fig. 7 is an enlarged broken top plan view, showing the gage by which the bit is guided during the grinding. Fig. 8 is a view of the tool supporting rod. Fig. 9 is a detached view of the auxiliary shaft and related parts. Fig. 10 is a broken front side elevation, showing the holder tilted away from the abrading disc. And Fig. 11 is the bottom faceview of the gage.

in the drawings, 2 represents the central body portion of the plane, 2 and 2 are respectively the aligning front and rear portions: of the bed,whose plane bottom surfaces ride frictionally over the work. The specilic means for connecting these parts are unimportant and will not" be described in this case. The back portion of the central body 2, comprises a hollow cylinder 2", into which isinserted an electric motor l, the latter being enclosed by casing l. The forward side of the body 2 is open, as 2, for the escape of chips and dust resulting from the planing. Adjacent the opening 2 the main body is formed with an outwardly project ing hub 2 P represents the armature shaft of the motor, which is usually fitted with a chuck or coupling a into which is screwed a short extension shaft 5 tl at supports the usual rotary tool 5, wiieh in the present case, preferably comprises a barrel 5 that telescopes the shaft, and a number of spiralshaped circumferential cutting blades 5. The outer end of shaft 5 is reduced and ournals in a bush-bearing 5", which is externally threaded for screwing into the hub 2 The front side (2) of section 2 is formed with a threaded perforation 2 for use in attaching parts of the tool-grinding mechanism. The facing ends of the sections 2-2 are preferably spaced sufficiently to provide the necessary clearance for the tool 5 to perform its work, as shown Fig. 2. The depth of the cuts by the tool 5 is controlled by the forward section 2', and for this purpose, the said section is arranged to be raised and lowered, by a mechanism (not shown), which is actuated by a manually rotatable dial 3. The dial 3 usually bears several markings to indicate different depths of the cuts by the tool, as shown in Figs. 1 and 4. 'The tool 5 preferably arranged to cut or level a surface to the plane of the bottom portion '2 but not any deeper, and when the diame ter of the tool is reduced by frequent grindings, the bed portion 2* may be raised to the cutting level of the tool, by the operator manipulating a screw 3. The bit 5 is preferably driven at high speed by the motor a, and the current for the motor may be controlled by a switch 5 carried by a handle 2 During the planing operations the device is propelled forwardly by the operator, by means of the handle 2. When the plane is employed for leveling the narrow edges of boards, and the like, it is necessary to provide suitable means for guiding and holding the plane exactly level. This is accomplished by means of a depending guard 6, which is preferably hinged (notshown) to the rear bottom corner or edge of the body 2, and is adjustable by means of a slotted arm 6 and a thumb-nut W, as shown in Fig. 6. The guard 6 may be employed for effecting the leveling or planing of surfaces at various angles relatively to the horizontal,

in a well-known manner. My bit grinding mechanism comprises the following parts:

The first step in the grinding work con sists of removing the shaft 5 and the tool 5 from the body 2 and substituting therefor a similar shaft 7, whose inner end is threaded V for screwing into the chuck 4c". The opposite end of shaft 7 is journaled in an externally threaded bushing 7?, which is adapted to be screwed into the hub 2 the same as the bushing 5". The shaft 7 is provided with diametric holes 7, by which the shaft may be rotated while it is being applied and removed, by the insertion'of a suitable lever or tool. The outer end of shaft 7 is threaded and projects beyond the bushing 7 and supports an emery or like abrading disc 7, which is held in place by a nut 7.

8 represents a tool holder of peculiar shape, which is formed with a hub 8 that slips loosely over and pivots upon a stud 8 the said stud having one end threaded for screwing into the perforation 2 of the sect-ion 2 Adjacent the hub 8 the holder is formed with an elongated body portion 8 which is disposed at an angle to and whose axis substantially intersects the axis of the shaft 7 The body 8 is normally positioned at an angle to the bottom plane of the sections 2-2 (see Fig. 10.), and its free end also inclines forwardly away from the front side of the plane, as best seen in Figs. 4 and 7. The opposite ends of the body 8 are bored out to loosely receive a rod 9, that supports the bit during the grinding opuntil it engages the pin 9", the nut 9 is then applied and tightened up for rigidly connecting the bit to the rod. The rod 9 is considerably longer than the body 8, and during the grinding of the bit, the said rod is reeiprocated to an extent substantially equal to the length of the bit, as shown by the full and dotted lines in. Figs. l and 5. The upper end of rod 9 has a knurled head 9, by which the operator twists the rod while the latter is being reciprocated. This twisting of the rod and bit in the direction indicated by the arrow in Fig. 7, causes the cutting blades 5 to describe a spiral path beneath the abrading disc when the tool is moved towards the hub 8-. At the end of each downward or grinding stroke of the rod and tool. the operator rotates the tool in the same direction sufliciently to bring the next blade 5" into the grinding position and then withdraws the rod upwardly again to the full line position of Figs. 4, 5, 6 and 7, in readiness for the next grinding stroke, and so on. At the opposite side of the hub 8, the holder is formed with an upwardly and a rearwardly extending arm as 8 8, which are arranged to overlie the flange 2" that forms the front side of the section 2. The arm 8 is bored out and is fitted with a plunger 10 whose free end is normally held in engagement with the flange 2 by a spring 10, and the extent of the axial movement of the plunger towards the said flange is controlled by a. screw 10% whose head acts as a stop, as may be understood by reference to Figs. 5 and 10. The tension of spring 10 tends to tilt the holder at the end of each grinding stroke of rod 9, as shown in Fig. 10. This swings the bit 5 away from the grinding disc 7 and enables the operator to adjust the bit for bringing the next cutting blade into the grinding position without interference or injury by the disc. The arm 8 of the holder is threaded to receive an adjusting screw 12 whose threaded end also registers with the flange 2*. In practice, the screw 12 is adjusted to provide a clearance of about one-eighth of an inch. This enables the spring 10. to tilt the holder, as shown in Fig. 10. When everything is in readiness for grinding the bit, the operator grasps the screw 12 with one hand and depresses the arm 8 (see Fig; 5), while with the other hand he pushes and twists the rods 9 downwardly, as indicated by the dotted lines in Figs. 4 and 5. When he has completed the grinding'of each blade he relaxes the pressure on the arm 8 and spring 10 instantly swings body 8 and the bit 5 away fill from the disc 7 {see Fig. 10), where it remains until he is ready for the next grinding stroke.

In order that the circumferential surfaces of the blades 5 may be presented to the abrading disc 7 in a manner to efiect true and even grinding ot the blades, I provide a gage 13, which comprises a substantially U-shaped sheet metal body, one arm 13 of which is disposed beneath the holder 8, and is spaced therefrom by a boss 13 to which it is secured by screws 13. This lower arm of the gage is preferably slotted (see Fig. 11), so as to enable the body to be moved towards and away from the disc 7, as indicated by the dotted lines in Figs. 4 and 'Z'. The top arm 13 ot' the gage partially overlies the bit, and its free end frictionally en gages one side or" the adjacent blade 5, and supports the said blade at the proper angle during the grinding. The adjustment of the gage 13 towards and away from the disc 7 increases or decreases the bevel for providing greater or less clearance for the blades. The operator, by a slight twisting pressure on the rod 9 may readily maintain the contact of the blade with the gage during the downward stroke of the said rod. This insures the true and uniform grinding of the blades, and only requires sutiicient care to maintainthe constant engagement of the gage with the blades throughout the grinding strokes. By this arrangement of the grinding mechanism, any person of ordinary skill may readily and quickly effect the satisfactory grinding of the tool.

The plane is supported during the grindoperation by a bracket 14, comprisinga split cylindrical portion 1%,which may be clamped around the motor 4,, by means of a screw l4; that engages perforated lugs adjacent the split, and a leg 14;, which is provided with spaced jaws I E-14 and a thumb-screw 14$, by which the bracket may be clamped to a bench or table, as 15 (see Figs. 4, 5 and 6.)

Having thus described my invention, what I claim, is-

1. In combination with a portable power.

plane having a rotary cutter, rotary grinding means for sald cutter, means to mount the i said mounting means to permit rotation and reciprocation or the cutter past the grinder whereby sharpening of the cutter is effected,

2. In combination with a portable power plane having a rotary cutter, rotary grinding means for said cutter, means to mount the grinder beyond one side of the plane interchangeably with the rotary cutter, means to support the cutter beneath the grinderwhereby the cutter may be manually tilted toward said grinder when pressure is applied to the supporting means, means to mount the cutter on said supporting means to permit rotation and reciprocation of the cutter past the grinder, and means to shift the supporting means and cutter away from the grinder when the pressure is removed.

3. In combination with a portable power plane having a rotary cutter, rotary grinding means in? said cutter, means to mount the grinder beyond one side of the plane interehangeably with the rotary cutter, means to pivotally support the cutter beneath the grinder whereby the cutter may be manually tilted toward said grinder when pressure is applied to the supporting means, means to mount the cutter on said supporting means to permit rotationand reciprocation of the cutter past the grinder, and spring means to shift the supporting means and cutter away from the grinder when the pressure is removed.

4. In combination with a portable power plane having a rotary cutter, grinding means for'said cutter, means to mount the grinder beyond one side of the plane interchangeably with the rotary cutter, a detachable pin secured to one side of the plane adjacent the grinder, a cutter holder pivotally mounted on said pin whereby the cutter and holder may be manually tilted toward said cutter, and means to support the cutter on said pivoted holder to permit rotation and reciprocation of the cutter past the grinder to effect sharpening of the cutter.

' In testimony whereof I afiix my signature.

RAY L. CARTER. 

